(a) Technical Field of the Invention
The present invention relates generally to waveguide arrays. More particularly, the present invention relates to a waveguide array wherein the input waveguides are selectively coupled to the output waveguides by switches and the aperture used to connect to the waveguide is matched only when the input waveguide is disconnected from the output waveguides.
(b) Description of Related Art
Waveguides are often used for the transmission of high-frequency signals, such as signals in the Ku band. In communications application, it is often desirable to connect a particular input waveguide to one of several different output waveguides. This allows for easier signal passing and handling functions.
In the past, this signal switching has been performed by using a microwave switch matrix (MSM) constructed from fully integrated striplines. In the MSM, each input waveguide is split into two branch striplines. A switch is used to control which of the branch striplines will be used to carry the signal. These branch striplines are further split by additional hybrids each having a switch. This splitting process continues until there are as many branches as there are output waveguides. One branch from each input waveguide is then connected to each output waveguide through proper switch selection of the stripline hybrid.
As the number of output waveguides increases, the number of hybrids, branches, and switches grows rapidly. Each of these hybrids adds 3 dB of loss to the switching system. Further, transmission line losses increase with increasing frequency. Additionally, the circuit board layout area required for the MSM grows quickly as the number of branches grows.
Accordingly, there is a need for a waveguide switch matrix that has a low switching mechanism reactance. Additionally, it is desired that the matrix require a relatively small physical layout area that does not increase exponentially as the number of outputs increases.